Microsoft Copilot vs on-premise AI: cost and compliance, worked through.

If your practice runs on Microsoft 365, Copilot is the path of least resistance: it arrives inside the tools your team already uses, through the procurement channel you already have. That convenience is real. So is the arithmetic once you multiply a per-seat licence across a growing business, and so is the fine print on where the AI processing actually happens. All Microsoft claims below link to Microsoft's own documentation.

What Microsoft gets right

• Deep Microsoft 365 integration. Copilot works inside Outlook, Word, Teams and Excel with your tenant's permissions model. Nothing else integrates that natively.
• Familiar procurement and enterprise certifications across the Microsoft cloud.
• Australian storage at rest. For Australian tenants, Copilot interaction content and the semantic index are stored at rest in Microsoft's Australian data centres (Microsoft data residency documentation).

The two things to weigh

1. Where the AI actually runs

Storage and processing are different commitments. Microsoft's own documentation is careful here: interaction data is stored at rest in Australia, but model inference can route through regions outside Australia depending on load and configuration. Microsoft has announced in-country Copilot processing for Australia, expected by the end of 2026 (Microsoft announcement). Until that lands and you verify it applies to your tenant, an Australian business should assume prompts can be processed offshore. And in any posture, the material is processed on Microsoft's cloud under a US provider's legal exposure, which is the structural difference from a unit in your office.

2. The per-seat arithmetic

Microsoft 365 Copilot is licensed per user, per month at Microsoft's published Australian rates, on top of a qualifying Microsoft 365 licence. Because it is priced per person, the economics track your headcount: for small teams the Copilot bill is usually well under a unit, often by half or more, and the case for a unit at that size is data control rather than the invoice. Costs typically converge in the tens of staff, and past that point per-seat spend keeps climbing with every hire, commonly 40 to 90 percent above unit-based pricing at larger sizes, while a unit's price does not move with headcount. Our cost page sets out how Dominion pricing works. What the unit buys at every size is the sovereignty question answered structurally: client material that is never transmitted to any provider, plus a model that learns your business rather than everyone's.

Which one fits

Copilot earns its seat where the work is general Microsoft 365 productivity: email triage, meeting summaries, first drafts from your inbox. The unit earns its place where the work touches client matters, precedent and confidential knowledge. Plenty of businesses will land on Copilot for some staff and Dominion for the practice; the mistake is assuming the M365 logo settles the confidentiality analysis.

Common questions